Writing instrument



FIG. 1 is a perspective view of a writing instrument showing a new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a right view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines are shown for the purpose of illustrating environmental subject matter and parts of the writing instrument that form no part of the claimed design. 

CLAIM The ornamental design for a “writing instrument,” as shown and described. 